Commit 862d8312 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

tty: make tty_class a static const structure 



Now that the driver core allows for struct class to be in read-only
memory, move the tty_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Reviewed-by: default avatarJiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/2023040250-landowner-unfitted-11f4@gregkh


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2243acd5

drivers/tty/pty.c

+1 −1
Original line number Diff line number Diff line
@@ -931,7 +931,7 @@ static void __init unix98_pty_init(void) 
	if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||

	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)

		panic("Couldn't register /dev/ptmx driver");

	device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");

	device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");

}



#else

drivers/tty/tty_io.c

+11 −13
Original line number Diff line number Diff line
@@ -3070,7 +3070,7 @@ static struct device *tty_get_device(struct tty_struct *tty) 
{

	dev_t devt = tty_devnum(tty);



	return class_find_device_by_devt(tty_class, devt);

	return class_find_device_by_devt(&tty_class, devt);

}
@@ -3143,8 +3143,6 @@ int tty_put_char(struct tty_struct *tty, unsigned char ch) 
}

EXPORT_SYMBOL_GPL(tty_put_char);



struct class *tty_class;



static int tty_cdev_add(struct tty_driver *driver, dev_t dev,

		unsigned int index, unsigned int count)

{
@@ -3239,7 +3237,7 @@ struct device *tty_register_device_attr(struct tty_driver *driver, 
		return ERR_PTR(-ENOMEM);



	dev->devt = devt;

	dev->class = tty_class;

	dev->class = &tty_class;

	dev->parent = device;

	dev->release = tty_device_create_release;

	dev_set_name(dev, "%s", name);
@@ -3294,8 +3292,7 @@ EXPORT_SYMBOL_GPL(tty_register_device_attr); 
 */

void tty_unregister_device(struct tty_driver *driver, unsigned index)

{

	device_destroy(tty_class,

		MKDEV(driver->major, driver->minor_start) + index);

	device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index);

	if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {

		cdev_del(driver->cdevs[index]);

		driver->cdevs[index] = NULL;
@@ -3510,13 +3507,14 @@ static char *tty_devnode(const struct device *dev, umode_t *mode) 
	return NULL;

}



const struct class tty_class = {

	.name		= "tty",

	.devnode	= tty_devnode,

};



static int __init tty_class_init(void)

{

	tty_class = class_create("tty");

	if (IS_ERR(tty_class))

		return PTR_ERR(tty_class);

	tty_class->devnode = tty_devnode;

	return 0;

	return class_register(&tty_class);

}



postcore_initcall(tty_class_init);
@@ -3643,13 +3641,13 @@ int __init tty_init(void) 
	if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||

	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)

		panic("Couldn't register /dev/tty driver\n");

	device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");

	device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");



	cdev_init(&console_cdev, &console_fops);

	if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||

	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)

		panic("Couldn't register /dev/console driver\n");

	consdev = device_create_with_groups(tty_class, NULL,

	consdev = device_create_with_groups(&tty_class, NULL,

					    MKDEV(TTYAUX_MAJOR, 1), NULL,

					    cons_dev_groups, "console");

	if (IS_ERR(consdev))

drivers/tty/vt/vt.c

+1 −1
Original line number Diff line number Diff line
@@ -3539,7 +3539,7 @@ int __init vty_init(const struct file_operations *console_fops) 
	if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||

	    register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)

		panic("Couldn't register /dev/tty0 driver\n");

	tty0dev = device_create_with_groups(tty_class, NULL,

	tty0dev = device_create_with_groups(&tty_class, NULL,

					    MKDEV(TTY_MAJOR, 0), NULL,

					    vt_dev_groups, "tty0");

	if (IS_ERR(tty0dev))

include/linux/tty.h

+1 −1
Original line number Diff line number Diff line
@@ -387,7 +387,7 @@ extern struct ktermios tty_std_termios; 


int vcs_init(void);



extern struct class *tty_class;

extern const struct class tty_class;



/**

 *	tty_kref_get		-	get a tty reference